Feeding device for stokers



Feb. 19, 1935.

w. D. BURTON FEEDING DEVICE FOR STOKERS Filed Nov. 5, 1931 Patented Feb. 19, 1935 Combustioneer, Inc., tion of Illinois Warren Dean Burton, Goshen, lnd assignor to Goshen, Ind, a corpora- Application November 5, 1931, Serial Nb. 573,089

5 Claims.

The present invention relates to feeding devices for stokers and particularly for stokers in which fuel is automatically supplied from the bottom portion of a hopper.

Coarse, dry fuel moves readily downward in a hopper to the discharge opening thereof. However, finely comminuted fuel, particularly when wet, tends to pack and bank and will arch over the feeding mechanism. Partial agitation will not bring down the fuel but will only cut a swath in the mass without dislodging the rest. 0bviously, failure of the fuel to feed uniformly is highly objectionable.

An object of the invention is to provide, in conjunction with a fuel agitating device, a new and improved means for driving the device.

Another object of the invention is to provide an improved driving mechanism for a fuel hopperagitating device, which mechanism may be rendered operative or inoperative at the will of the operator.

pensive in construction.

Other objects and advantages will become apparent in the following description and from the accompanying drawing, in which:

Figure 1 is a plan view of a device embodying the features of the invention, parts of the hopper being in section on the line 1-1 of Fig. 4.

Fig. 2 is a side elevation of the device with parts of the hopper broken away.

Fig. 3 is a fragmentary elevational view of the left-hand end of the device as seen in Fig. 2.

Fig. 4 is a vertical transverse section through the device as indicated by the line 4-4 of Fig. 1.

Fig. 5 is a detail view showing a part of the drive mechanism in plan.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawing and will herein describe in detail the preferred embodiment, but it is to be understood that -I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawing, the invention is adapted for various types of stokers embodying feed hoppers and for pur poses of illustration is described in connection with a. vertical hopper 10 having a conveyer screw 5 11 extending laterally through the bottom for discharging the fuel from one side thereof. In this instance, the hopper 10 is rectangular in cross section and embodies a base 12 having inclined opposed side walls 13 and i4 defining a V-shaped trough 15 in which the feed screw 11 is disposed. End walls 16 and 17' complete the base structure. Walls 18, forming the upper portion of the hopper 10, are supported by the several walls of the base 12 and are arranged immediately above the base to flare outwardly for a considerable distance, after which the walls taper inwardly to define a somewhat restricted open top. A suitable closure 19 is provided for the open top, one preferred form comprising a flat plate hinged, as at 20, to one of the side walls.

The conveyer screw 11, which comprises a helical plate 21 carried by an axial shaft 22, extends through one wall of the base (in this instance, the wall 17) into a duct 23 which leads to the fire box of the stoker (not shown). The opposite end of the shaft 22 extends through the other end wall 16 into a gear box housing 24 within which a well-known type of change speed gear mechanism (not shown) drivingly connects the shaft with a source of power such as an electric motor The illustrated stoker embodies a driven shaft 26 which operates a conveyer screw (not shown) for removing ashes from the retort. The shaft- 26 is driven in any suitable manner and preferably from the shaft 22 through a chain and sprocket connection (not shown) but' located within a housing 27. The shaft 26 is spaced from and parallels the shaft 22 and extends externally beneath a. fiat horizontal portion 28 (Fig. 4) provided on the base 12 of the hopper by enlargingone side thereof. The shaft 26 carries a cam 29 for engagement by a cam roller 30 mounted on one end of a lever 31 which is supported intermediate its ends by a horizontal pivot 32 mounted on a stationary part of the device. The cam is shaped. to impart an intermittent reciprocatory movement to the lever 31 and the upper end of the lever carries an arm 33 for actuating a part of the ash removing mechanism of the stoker. This ash removing mechanism forms no part of the present invention and is not herein shown, but the general features thereof 55 are clearly described and illustrated in my copending application Serial No. 545,210, filed June 18, 1931.

The fuel agitating mechanism is located within the hopper and is arranged for movement throughout and into every part of the hopper. The mechanism is driven externally of the hopper with an intermittent movement and the driving connections are such that the reciprocatory movement'of the lever, which operates the ash removing mechanism, may be utilized. The agitator mechanism comprises a shaft 34 which extends vertically through the hopper at one side of the fuel conveyer screw and has its lower end extending through an aperture in the flat horizontal portion 28 of the base. A bracket 35 (Fig. 2), suitably secured to the under side of the flat portion, has a tubular bearing 36 for rotatably supporting the shaft 34. The upper portion of the bearing 36 is internally recessed and screw threaded to receive packing material 37 (Fig. 4) which is held in place by a conventional type of packing gland 38 engaging the screw threads on the bearing. I

A collar 39 pinned or otherwise secured to the agitator shaft 34 is disposed thereon for engagement with the upper surface of the packing gland to support the agitator shaft against downward axial displacement. The relationship of the collar and the packing gland prevents access of very fine particles of fuel to the bearing whereby to eliminate any unusual wear of the bearing. It is preferred that the upper end of the agitator shaft 34 be rotatably supported and for this purpose a tubular member 40, suitably aflixed to the closure 19, is arranged to encircle and support the upper end of the agitator shaft when the device is in operation.

A short distance above the collar 39, a sleeve 41 is rigidly secured to the agitator shaft, which sleeve has a laterally extending projection 42. An

agitator rod 43, secured to this projection, pivots about a horizontal axis and, in the rotary movement of the agitator shaft, describes an orbit within the hopper. The agitator rod is urged outwardly toward the walls of the hopper by such means as a spring 44 mounted in a cylinder 45 carried by the agitator shaft above the agitator rod and arranged to exert its tension on the agitator rod through an intermediate connecting link 46.

A preferred form of mechanism for driving the agitator shaft 34 comprises the following arrangement of parts: The lower end of the agitator shaft has a ratchet 47 rigidly secured thereto as by means of a pin 48. The hub of the ratchet preferably has a running abutment with the lower end of the bearing 36 to prevent axial movement of the agitator shaft in an upward direction. The ratchet 47 is actuated by means of a pawl 48 fashioned on an elongated arm 49, one end of which is loosely secured to the cam actuated end of the lever 31. For simplicity of construction, the pivot, by which the cam roller 30 is mounted on the lever '31, may be employed to support the arm 49 on the lever. The connection between the arm and the lever is such that pivotal movement, as well as horizontal swinging movement of the arm, is permitted. The arm extends past the ratchet 47 and such means as a contractile spring 50, connected between the free end of the arm and a stationary part of the structure, normally exerts a force for holding the pawl of engagement with the ratchet in order that the operator may render. the agitating device operative or inoperative at his option. To this end, a stationary part of the hopper has a latch member 51 is pivotally secured thereto, as at 52, and disposed in overlying engagement to the pawl arm 49. A notch 53 in the latch is positioned for engagement by the pawl arm in a position wherein the pawl will be held out of engagement with the ratchet against the tensionof the spring 50. It is preferred that the ends of the pawl arm 49 and ratchet 51 extend outwardly beyond the base of the device as a whole so that the parts are conveniently disposed for manipulation of the operator.

In describing the operation of the device, it will be considered that the motor 25 is running to operate the fuel conveyer screw through the shaft 22, and the ash removing mechanism through the shaft 26. As the shaft 26 rotates, the cam 29 thereon produces reciprocatory movement of the lever 31 which, in turn, reciprocates the pawl arm 49. The intermittent engagement of the pawl 48 with the ratchet 47 produces a step by step movement of the agitator rod 43 through out the interior of the hopper whereby to dislodge the fuel therein for movement by gravity into the range of the conveyer screw 11. When the device is operating upon certain types of fuel which will feed without agitation, the operator by swinging the end of the pawl arm outwardly causes'the notch 53 in the latch 51 to drop by gravity into engagement with the pawl arm whereby the agitator drive is disconnected. This feature is advantageous since it diminishes power consumption wherever the nature of the'fuel permits it to be used.

To reestablish the driving" connection of the agitator mechanism, it is only necessary for theoperator to raise the latch 51 to disengage the notch from the pawl arm whereupon the spring 50 reestablishes the driving engagement of the pawl and ratchet. In order to maintain the pawl properly positioned with respect to the ratchet, such means as a pair of fingers 54 (Figs. '4 and 5) carried by the upper and lower sides of the pawl arm adjacent the pawl extend therefrom in straddling relationship to the upper and lower faces of the ratchet.

It will be apparent from the foregoing that the agitator mechanism is driven by means which is positive in its operation, simple in construction, and which may be rendered operative or inoperative at the will of the operator.

I claim as my invention:

1. In a stoker, in combination, a fuel hopper, a fuel agitating mechanism located within said hopper and including an agitator shaft extending through the bottom of said hopper, an ash handling mechanism including a reciprocating member, driving connections between said reciprocating member and said agitator shaft for driving said agitator shaft-intermittently, said driving connections including a ratchet on said agitator shaft, a pawl engaging said ratchet, and an arm actuated by said reciprocating member and carrying said pawl. i

2. In a stoker having a fuel hopper and means for agitating fuel within said hopper including a vertical shaft, the combination of a ratchet on the lower end of said shaft, a pawl for engaging said ratchet, means for reciprocating said pawl, means for normally holding said pawl resiliently in constant engagement with said ratchet, and a pawl engaging latch operable when engaged therewith to hold saidpawl out of engagement with said ratchet.

3. In a fuel stoker; in combination, an upright fuel hopper, means for agitating fuel within said hopper, said means including a vertical shaft and a generally laterally extending arm mounted on said shaft to revolve therewith, a rotatable toothed ratchet having a driving connection with said shaft, a reciprocating arm extending tangentially of said ratchet and carrying a pawl for engaging said ratchet, a lever extending substantially perpendicularly to said arm, one end of said arm being pivotally connected to said lever, a spring acting on said arm and tending to pivot said arm about said lever toward said ratchet to urge said pawl into engagement with said ratchet,

and power drive means for oscillating sa'id lever to effect unidirectional intermittent rotation of said shaft.

4. In a stoker, in combination, an upright fuel hopper having a cover, a bearing on the underside of said cover, a solid vertical agitator shaft in said hopper and extending outwardly through the bottom thereof, the upper end of said shaft being journaled in said bearing, an agitating arm pivotally connected at one end directly to the lower portion of said shaft to revolve therewith and for independent vertical swinging movement, the other end of said arm extending upwardly and outwardly from said shaft toward the side walls of said hopper, resilient means carried by said shaft and tending to swing said arm outwardly and downwardly toward said walls, and drive means connected to the lower end of said shaft outside of said hopper for rotating said shaft intermittently.

5. In a stoker, in combination, an upright fuel hopper, a single vertical agitator shaft in said hopper and'extending outwardly through the bottom wall thereof and journaled at its lower end in said wall, an agitating arm pivotally connected at one end directly to the lower journaled portion said shaft to revolve therewith and for independent vertical swinging movement, the other end of said arm extending upwardly and outwardly from said shaft toward the side walls of said hopper, a housing attached directly to said shaft, a spring mounted in said housing, means for imparting the action of said spring to said arm to urge the latter to swing toward said side walls of said hopper, and power drive means for rotating said shaft intermittently.

WARREN DEAN BURTON. 

